Ballistic modifiers and synthesis of the ballistic modifiers

ABSTRACT

A new class of ballistic modifiers and the synthesis thereof is disclosed herein and are used in propellants either individually or as admixtures in percentages of approximately 0.5 to 6 weight percent to impart mesa or plateau burning rate characteristics over a wide pressure range and reduce the temperature sensitivity of the propellants in relation to burning rates. The modifiers are chelate type compounds comprised of lead and/or copper, and various predetermined molar ratios of compounds such as salicylic acid and beta-resorcylic acid.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of applicants' co-pending applicationSer. No. 58,133, filed Sept. 11, 1970.

BACKGROUND OF THE INVENTION

Existing similar modifiers of the type disclosed herein give suitablepropellant ballistic modification, but in general the existing modifiersare chemically unstable and hydrolyze during propellant processing andstorage to create serious problems. The monobasic cupric salicylate andlead beta-resorcylate modifiers system currently used in the DRAGON sidethruster and canister motors is an example of such an unstable system.The excess lead beta-resorcylate hydrolyzes to give beta-resorcylic acidas a product. The acid subsequently concentrates on the propellantsurface and causes propellant ignition failures at low temperatures. Asa result of this inadequate modifier, propellants with the inadequatemodifier must be rejected. Therefore, it is an object of this inventionto provide ballistic modifiers that are stable and do not cause adverseside effects when incorporated into propellant compositions.

Another object of this invention is to provide a novel process ofsynthesizing ballistic modifiers according to this invention.

A further object of this invention is to provide ballistic modifiersthat can be used in solvent, solventless and casting powder typeprocesses.

Still another object of this invention is to provide ballistic modifiersthat are especially adapted for use with double base propellants.

A still further object of this invention is to provide ballisticmodifiers in propellant compositions to produce mesa and/or plateauburning rate characteristics.

SUMMARY OF THE INVENTION

This invention relates to chelate type ballistic modifiers for doublebase propellants and the processes of synthesis of the ballisticmodifiers. The ballistic modifiers are synthesized by either reactingmetal ions with chelating agents in a reaction liquid or by reactingchelating agents that already contain metal with each other in thepresence of a reacting liquid. The reaction is carried out from aboutroom temperature up to about 100° C. The temperature at which thereaction takes place is chosen according to the speed of reactiondesired. Reaction is faster at the higher temperature. The ballisticmodifiers of this invention are utilized in double base propellantscontaining other ingredients such as nitrocellulose, nitroglycerine,Di-n-propyl adipate, 2-nitrodiphenylamine, candelilla wax and otherdesired ingredients as appropriate.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graph showing burning rate versus pressure of propellantComposition-E as illustrated in Table IV herein below; and

FIG. 2 is a graph showing burning rate versus pressure of propellantComposition-F as illustrated in Table IV herein below.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The new chelate type ballistic modifiers described in this invention area significant advancement in ballistic modifier technology for doublebase propellants. When they are used in amounts of approximately 0.5 to6-percent by weight in double base propellants, they impart mesa and/orplateau burning rate characteristics to the propellant over a widepressure range, and reduce its temperature sensitivity (π_(K)). Asignificant property of these modifiers is that they are very stablechemically, and therefore are not altered during propellant processingand subsequent storage. This stability results in improved propellantballistic repeatability and reliability. These new modifiers are adaptedfor applications in double base propellants made by the solvent orsolventless process, where many current modifiers are inherentlyineffective or are chemically unstable and therefore unsatisfactory.

The currently used modifiers are lead and copper compounds of salicylicand beta-resorcylic acids. They generally react with each other duringpropellant processing to produce a variety of products that aredifficult to control, and they are often hydrolyzed by the processingsolvents. Besides the obvious difficulty of obtaining reproduciblepropellant ballistic performance from batch-to-batch with currentmodifiers, some of the reaction products produced during processing andstorage have a detrimental effect on the propellant performance. Anexample is the beta-resorcylic acid exudate problem of the DRAGON sidethruster propellant.

The modifiers described in this invention disclosure can be substitutedfor the current modifiers in most double base propellants; therebyeliminating the instability problems. Moreover, certain of these newmodifiers will produce propellant mesa and/or plateau burning ratecharacteristics with low π_(K) in the pressure region of 5000 to 10,000psi.

STRUCTURE AND PROPERTIES

A list of the most important ballistic modifiers is given in Table Ibelow. Table I also shows the correct relative molar ratios of reactantsto use for the preparation of each compound. The compounds all have thesame general type of chelate structure, but they may be divided into twotypes. In the first type the modifier molecule contains two ligands ofthe same bidentate chelating agent, and in the second type the twobidentate ligands are different. The structures of both types ofmodifiers are illustrated in Table II below. Some of the modifiers alsocontain water of crystallization that can be removed at elevatedtemperature. Compound-1 for example, contains one water ofcrystallization at temperatures below 160° F., but is converted to theanhydrous form, shown in Table II at temperatures above 160° F.

                                      TABLE I                                     __________________________________________________________________________    REACTANTS AND THEIR RELATIVE PROPORTIONS FOR THE PREPARATION OF NEW           BALLISTIC MODIFIERS                                                           Metal Ions,    Chelating Agents, Gram - Moles                                 Grams - ions   2,4-Dihydroxy-                                                                        2-Hydroxy-                                                                            2,5-Dihydroxy-                                                                        0-Acetamido-                                                                         4-Acetamido-                                                                         Salicyl-                                                                           Benzoic             Compound                                                                            Cu.sup.++                                                                          Pb.sup.++                                                                         benzoic Acid                                                                          Benzoic Acid                                                                         benzoic Acid                                                                           benzoic Acid                                                                         Salicylic                                                                            amide                                                                              Acid                __________________________________________________________________________    1     1    1   2                                                              2     1    1           2                                                      3     1    1                  2                                               4     1    1                           2                                      5     1    1                                  2                               6     1    1                                         2                        7     1    1   1       1                                                      8     1    1   1                       1                                      9     1    1           1               1                                      10    1    1   1                              1                               11    1    1           1                      1                               12    1    1   1                                     1                        13    1    1   1                                          1                   14    1    1           1                                  1                   __________________________________________________________________________

                                      TABLE II                                    __________________________________________________________________________    CHEMICAL STRUCTURES OF SELECTED BALLISTIC MODIFIERS                           __________________________________________________________________________     ##STR1##                                                                                             ##STR2##                                               ##STR3##                                                                                             ##STR4##                                              __________________________________________________________________________

It is apparent from examining Tables I and II that a much larger numberof ballistic modifier compounds can be synthesized by varying the typesand combinations of the chelating agents, and possibly the metal ionsand their valences. Based on past experience, the metal, lead, willprobably be required in the compound for it to have ballistic activity.Although only compounds containing the metals, lead and copper, in their+2 valence states are illustrated, there are several other metals thatmay be used such as: silver, cobalt, nickel, zinc, and bismuth.

The properties of a particular ballistic modifier and hence itsperformance in propellants depends on the strengths and stabilities ofthe metal--ligand bonds. A major requirement for the synthesis of theseballistic modifiers is that one of the ligands must have two functionalgroups on an aromatic or heterocyclic ring, and one of the groups mustbe in an ortho position with respect to the other. The other ligand musthave at least one functional group on an aromatic or heterocyclic ring.Furthermore, these functional groups must contain donor atoms capable ofcombining with the metal ions by donating a pair of electrons as shownin Table II. Each ligand may also contain one or more additionalfunctional groups on the ring that do not enter into the synthesisreaction. These additional functional groups also affect the chemicaland thermal stability of the modifier, and its reactivity with NO₂radicals during propellant combustion. Consequently, ballistic modifierscan be tailored for specific propellant applications by modifying thestructures of the ligands. Functional groups that may react with themetal ions by the replacement of hydrogen are: --COOH, --SO₃ H, --OH(phenolic), ##STR5## where R is an alkyl radical with from 1 to 20carbon atoms. Functional groups that may coordinate directly with themetal ions are: ═O, --NH₂, --NH, --N═, --O--R₁, ═NOH, --OH (alcoholic),--S--(thio ether), --AsR₂, and --PR₂ (R=alkyl radical with 1 to 20carbon atoms, the two R's may be the same or different alkyl radicals).

All of the compounds in Table I are largely insoluble in water and mostorganic liquids. They are highly resistant toward hydrolysis and arethermally stable under nitrogen at temperatures in excess of 200° C.Compound 1, for example, is not affected chemically by boiling in waterfor 15 minutes and its solubility in boiling water is less than 0.1%. Itis slightly soluble in dimethylformamide and pyridine, and is thermallystable under nitrogen at temperatures as high as 260° C.

SYNTHESIS

The relative proportions of the reactants for the synthesis of ballisticmodifiers of this invention have been given in Table I. The generalreaction equations are: ##STR6## where M₁ and M₂ may be the same ordifferent metal ions. Lead and copper in their +2 valence states are thepreferred ions. The types of lead and copper compounds used have asignificant influence on the quality of product obtained and itspercentage yield. The preferred lead compound is lead (II) oxide (yellowform), and the preferred copper compounds are copper (II) hydroxide, andbasic copper (II) carbonate. These compounds under the correct reactionconditions will yield ballistic modifiers having purities exceeding 98%by weight in yields of 90-100% by weight. Other compounds that can beused are the nitrates, acetates, sulfates, and chlorides of the metals.The use of these compounds, however, often results in side reactions,and impure products with substantially reduced yields. Water is thepreferred reaction liquid. Organic liquids such as acetone and ethylalcohol have been used, but they offer no apparent advantages overwater.

Reactions are carried out in a vessel at atmospheric pressure bythoroughly agitating a mixture of the reactants in distilled ordeionized water at elevated temperature until reaction is complete. Theorder of addition of the reactants must be controlled when the modifierbeing synthesized contains two different ligands. The optimum order ofaddition is predetermined for the specific modifier. Reactiontemperatures from room temperature (25° C.) to 100° C. have been used,but the preferred temperature is 65° C. Although most of the modifierscan be synthesized at room temperature, the reaction time isunnecessarily long, and it is difficult to remove any unreacted startingmaterials because of their low solubility in the supernatant liquid. Thereaction rate is accelerated at temperatures above 65° C. but thepossibility of decomposing some of the chelating agents increases. Thisis particularly true for beta-resorcylic acid which can decompose toresorcinol. The normal reaction time at 65° C. for stoichiometricamounts of the reactants is three hours. This reaction time can bereduced to 0.5-1 hour by using a 5% by weight excess of the chelatingagents. The use of nitric acid to reduce the pH of the reaction mediumor sodium hydroxide to increase the pH is not recommended as theseadjustments markedly lower the yields and often result in undesirableside reactions. The rate and extent of the reaction is continuouslymonitored by means of a recording pH meter. The reaction is completewhen the reaction medium attains a constant pH value. The reactionslurry is filtered while hot to remove the product from the supernatantliquid, and the product is thoroughly washed with three equal portionsof distilled water at 65° C. Filtrations of laboratory quantities of themodifier are made with a Buchner funnel using Whatman #42 filter paper.The modifier is then dried at 110° C. to a constant weight, and lightlyground in a mortar and pestle to a uniformly fine powder. In some casesthe modifier may be dried to constant weight at a lower temperature toobtain the hydrated form of the modifier. As mentioned, copper (II)hydroxide and basic copper (II) carbonate are the preferred coppercompounds. The carbonate is cheaper and generally of higher purity, butit produces carbon dioxide gas which results in foaming of the reactionmixture. The hydroxide is, therefore, recommended for the synthesis oflarge batches of the modifier when the forming produced by the carbonatecannot be tolerated.

Some of the modifiers listed in Table I can be synthesized fromcurrently available modifiers, which are copper and lead compounds ofsubstituted aromatic acids. This method of synthesis, however, is muchless desirable than synthesis from the basic lead and copper salts andchelating agents previously described for the following reasons: (1) thenumber of different modifier types that can be prepared is very limited,(2) the stoichiometric quantities of the metals and chelating agents cangenerally not be obtained, and this results in undesirable sideproducts; modifier products that are difficult to purify; and lowyields, (3) current modifiers such as monobasic cupric salicylate andlead beta-resorcylate are more difficult to prepare reproducibly and inhigh purity than the modifiers in Table I, and (4) the cost of preparingthe modifiers of this invention utilizing current modifiers instead ofthe basic raw materials, as shown in Table I, is considerably higher.

Examples of reactions with current modifiers to synthesize the ballisticmodifiers of this invention are given in Table III below. Undesirableside products were obtained in each reaction. When the side products arewater soluble, as is the case for reaction-1, it is possible to obtain arelatively pure compound, but the yield is low (60-70% by weight).Sometimes a mixture of modifiers of this invention is obtained as shownby reaction-6. Reaction-6 also illustrates the case where the currentmodifiers, monobasic cupric salicylate and monobasic leadbeta-resorcylate, do not react in the laboratory under the conditionsdescribed unless an acid such as beta-resorcylic acid is added. Thesemonobasic compounds have been found, however, by propellant analysis toreact during propellant processing.

                  TABLE III                                                       ______________________________________                                        EXAMPLES OF NEW MODIFIER                                                      SYNTHESIS USING CURRENT MODIFIERS                                                  ##STR7##                                                                     Compound - 1 + other products.                                            2.  Monobasic cupric beta-resorcylate +                                            ##STR8##                                                                     Compound - 7 + other products +                                               unreacted starting materials.                                             3.  Normal cupric salicylate +                                                     ##STR9##                                                                     Compound - 2 + other products.                                            4.  Monobasic cupric beta-resorcylate +                                            ##STR10##                                                                    Compound - 7 + other products.                                                 ##STR11##                                                                    Compound - 2 + other products.                                            6.  Monobasic cupric salicylate +                                                 monobasic lead beta-resorcylate +                                              ##STR12##                                                                    Compound - 1 + Compound - 7 + other products.                             ______________________________________                                         NOTE:                                                                         Refer to Tables I and II for identification of the compounds formed.     

The following reactions illustrate the synthesis of selected ballisticmodifiers of this invention using basic starting materials:

EXAMPLE 1

Using a total of 10 g of reactants, Compound-1 was synthesized accordingto the following reaction: ##STR13##

The lead (II) Oxide (yellow form) was reagent grade, and the2,4-dihydroxybenzoic acid (beta-resorcylic acid) was practical grade.These chemicals were assumed to be pure. The basic copper (II) carbonateand a copper assay of 55.8% by weight, and this assay value was used todetermine the weight of basic copper (II) carbonate for the reaction.The reactants were weighed into a 250 ml graduated beaker, and 50 ml ofdistilled water was added. The mixture was stirred at room temperature(25° C.) to thoroughly wet the reactants, then additional distilledwater was added to bring the total volume to the 200 ml mark. Thereaction slurry was vigorously stirred throughout the remainder of thereaction by means of a Teflon coated magnetic stirring bar and the pH ofthe slurry was continuously recorded. An equilibrium pH of 3.8 wasestablished at room temperature, then the slurry was heated to thereaction temperature of 65° C. The initial application of heat resultedin partial solution of the 2,4-dihydroxybenzoic acid which lowered thepH to 3.6. Immediately after this initial lowering of the pH, thereaction rate began to increase thereby gradually increasing the pHduring the remainder of the reaction. The reaction was completed 3.5hours after addition of the reactants, as indicated by the attainment ofa constant pH of 5.45. The hot slurry was then filtered using a Buchnerfunnel and a Whatman #42 filter paper. The residue (Compound-1) waswashed with three 100 ml portions of distilled water at 65° C. and driedto constant weight in an oven at 160° F. The dried modifier was lightlyground with a mortar and pestle to break up agglomerates and produce afine light green powder. The yield was 98.6%, and subsequent chemicalanalysis of the modifier showed that its purity was greater than 98% byweight.

EXAMPLE 2

The procedure of example 1 was repeated in this example except that thereaction was carried out at room temperature (25° C.). The time requiredfor complete reaction to take place was 8 hours, and the pH increasedfrom an initial value of 3.75 to a final value of 6.55. The modifierresidue was washed with distilled water at 25° C. as described inexample 1. The dried modifier weight was 9.32 g which corresponds to ayield of 98.5%. The purity of the modifier was slightly less than thatof example 1. A portion of the modifier dried at 160° F. was furtherdried at 110° C., where it lost approximately 3% by weight,corresponding to one water of hydration.

EXAMPLE 3

The procedure of example 1 was repeated in this example except that a 5%excess of 2,4-dihydroxybenzoic acid by weight was used. The reactionwas: ##STR14## The time required for complete reaction to take place was1.75 hours. The initial value of the pH was 3.30 and the final value was3.95. The excess acid was soluble in the filtrate, and was completelyremoved from the residue (Compound-1) by washing with distilled water at65° C. The yield of Compound-1, dried at 160° F., was 96.4%, and itspurity was greater than 98% by weight.

EXAMPLE 4

In this experiment, Compound-1 was made on a 50 g scale according to thefollowing reaction: ##STR15## The steps of the procedure were the sameas for Example 1 except that the reaction was carried out in an 800 mlbeaker, and 600 ml of distilled water was used. The initial pH of thereaction mixture at room temperature was 3.60, and at the completion ofthe reaction was 5.60. The time required for complete reaction was 2.5hours after addition of the reactants. The product was dried to constantweight at 160° F. and ground to a fine light green powder. The yield was96.3% and the purity of the compound was greater than 99% by weight.

EXAMPLE 5

This example describes the synthesis of Compound-2 on a 10 g scaleaccording to the following reaction: ##STR16## The steps of theprocedure were the same as those of Example 1. The initial pH of thereaction mixture at 24° C. was 5.25. The reaction began to take placeimmediately, and leveled off at a pH value of 4.75 at 24° C. Heat wasthen applied to the reaction mixture; whereupon an additional portion ofthe 2-hydroxybenzoic acid dissolved thereby lowering the pH of theslurry to 3.88 at the reaction temperature of 65° C. After 40 minutes ofmixing, the pH of the slurry began to slowly increase as the reactionprogressed. The pH attained a constant value of 4.68 after three hoursreaction time indicating that the reaction was complete. The product wasremoved by filtration and dried to a constant weight at 110° C. Thedried powder was ground in a mortar and pestle to break up agglomerates,and weighed to determine the yield. The yield was 95.0%. Analysis of thecompound indicated that its purity was greater than 95% by weight.

EXAMPLE 6

This experiment was a repeat of Example 5 except that a 5% by weightexcess of the 2-hydroxybenzoic acid was used. This has the advantage ofincreasing the rate of reaction, and providing greater assurance thatthe copper and lead salts will completely react. Care must be exercised,however, to wash the excess acid from the desired product. The reactionwas: ##STR17## The steps in the procedure were the same as those givenin Example 1. The initial pH of the reaction slurry at 25° C. was 3.90.Heat was applied to raise the temperature of the reaction to 65° C. Thereaction was complete after 30 minutes. The final pH of the slurry was3.31. The product was removed from the supernatant liquid by filtration,dried to a constant weight at 110° C., and ground to a fine powder. Theyield was 94.1%. The purity of the compound was greater than 99% byweight.

EXAMPLE 7

This example describes the synthesis of Compound-7, and is typical ofthe procedure required to synthesize those modifiers containing twodifferent ligands in the molecule. The reaction was: ##STR18## Since twodifferent chelating agents are used, the order in which the reactantsare added to the reaction vessel must be controlled to avoid undesirableside reactions. The order of addition given here is one of several thatcan be used to prepare pure Compound-7. The basic copper (II) carbonate;2,4-dihydroxybenzoic acid; and 2-hydroxybenzoic acid were added alongwith 50 ml of distilled water to a 250 ml beaker, and the mixture wasstirred to thoroughly wet the solids. The total volume of the slurry wasthen adjusted to 200 ml with distilled water, and heated to 65° C. Thereaction mixture was vigorously stirred and the pH was continuouslyrecorded during the reaction. The pH equilibrated at 3.28, and 20minutes after addition of the first three reactants the lead (II) oxidewas added. The pH then gradually increased as the reaction progressedand attained a constant value of 4.70. The total reaction time was 2hours. The slurry was filtered using a Buchner funnel and Whatman #42filter paper. The residue (Compound-7) was then dried to a constantweight at 110° C., and ground in a mortar and pestle to break upagglomerates. The yield of Compound-7 was 90.0%, and its purity wasgreater than 99% by weight.

EXAMPLE 8

This example illustrates the synthesis of Compound-8, which contains twodifferent ligands. In the case of this particular compound, all of thereactants can be added to the reaction vessel at the same time. Thefollowing reaction was carried out: ##STR19## The steps of the procedurewere the same as given in Example 1. The initial pH of the reactionmixture at 24° C. was 4.30. The reaction immediately began to take placeat 24° C. and as a result the pH increased. When the reaction hadproceeded for 20 minutes and the pH had increased to 5.9, heat wasapplied to the reaction mixture. The pH then decreased to 4.65, afterwhich it increased again to a final constant value of 6.10. The totalreaction time from addition of the reactants was 1.5 hours. The slurrywas filtered and the residue (Compound-8) was dried to a constant weightat 110° C., and ground in a mortar and pestle. The yield of Compound-8was 94.7%.

EXAMPLE 9

This example describes the synthesis of Compound-1 by using currentballistic modifiers according to the reaction: ##STR20## The foregoing1:1 molar stiochiometry of the reactants is the closest that can beobtained to the true stoichiometry for compound-1. Nevertheless, thereaction produces a mole of salicylic acid which is not required, andwhich may enter into undesirable side reactions. The steps of thissynthesis were the same as those of Example 1. The initial pH of thereaction mixture at room temperature (25° C.) was 4.50. After 20 minutesof mixing, the pH dropped to 4.00 at which time heat was applied. The pHleveled off at 3.25 after 40 minutes at which time the temperature ofthe reaction medium had equilibrated at 70° C., and the reaction wascomplete. The yield of Compound-1 was 68.6% and its purity was greaterthan 98% by weight.

PROPELLANT APPLICATIONS

Compounds-1 and -7 have been evaluated in double base type propellants.The nominal compositions of the propellants are given in Table IV below.All the propellant compositions were made by a standard solventlessprocess. The burning rates of each composition as a function of pressurewere determined with cured propellant strands, and the heat of explosionwas also determined. The compositions containing Compound-1 hadballistic performance comparable to that of a double base propellantcontaining monobasic cupric salicylate and lead beta-resorcylatemodifiers. Composition-A containing 4% of Compound-1 had burning rateson the low side of the specification. Composition-B had higher and moreacceptable burning rates than Composition-A. Neither composition hasbeen observed to form exudate on the propellant surface during storage,as is the case with many compositions containing monobasic cupricsalicylate and lead beta-resorcylate. These experiments demonstratedthat Compound-1 can be substituted for the current ballistic modifiersof one or more double base propellants, resulting in improved ballisticrepeatability and storage stability. As anticipated, Composition-C whichcontained Compound-7 had mesa burning rate characteristics at a lowerpressure than the compositions containing Compound-1. Composition-D hadburning rate characteristics intermediate to those of the othercompositions. Composition-E had strand burning rates at the specifiedtemperatures of the propellant as depicted in FIG. 1 of the drawing, andComposition-F had strand burning rates at the specified temperatures asdepicted in FIG. 2 of the drawing.

The other compounds in Table I may be used as ballistic modifiers to actas catalysts in double base propellants. For example, compoundscontaining salicylates produce mesa and/or plateau burningcharacteristics at low pressures; whereas those containing resorcylatesproduce comparable characteristics at higher pressures. Some of thecompounds in Table I such as Compounds-8 and -10, have the potential ofreducing temperature sensitivity and producing mesa and/or plateauburning rate characteristics at pressures in the region between 4000 psiand 10,000 psi.

                                      TABLE IV                                    __________________________________________________________________________    NOMINAL COMPOSITIONS OF HEN-12 TYPE DOUBLE BASE PROPELLANTS CONTAINING        COMPOUNDS - 1 AND - 7                                                         Ingredients                                                                              Composition - A                                                                        Composition - B                                                                       Composition - C                                                                        Composition - D                                                                        Composition -                                                                          Composition -          __________________________________________________________________________                                                           F                      Nitrocellulose                                                                           49.0 ± 1.5                                                                          49.0 ± 1.5                                                                         49.0 ± 1.5                                                                          49.0 ± 1.5                                                                          49.0 ± 1.5                                                                          49.0 ± 1.5          (12.6 N)                                                                      Nitroglycerine                                                                           40.6     40.6    40.6     40.6     40.6     40.6                   Di-n-propyl adipate                                                                      3.3      3.3     3.3      3.3      3.3      3.3                    2-nitrodiphenylamine                                                                     2.0 ± 0.5                                                                           2.0 ± 0.5                                                                          2.0 ± 0.5                                                                           2.0 ± 0.5                                                                           2.0 ± 0.5                                                                           2.0 ± 0.5           Candelilla wax                                                                           0.1      0.1     0.1      0.1      0.1      0.1                    *Compound - 1                                                                            4.0      4.5              4.0      5.0                             *Compound - 7               4.0      1.0               5.0                    __________________________________________________________________________     *The compositions of these compounds are identified in Table I.          

We claim:
 1. The process of synthesizing ballistic modifiers, saidprocess consisting of mixing different metal ions selected from thegroup consisting of lead, copper, silver, cobalt, nickel, zinc andbismuth with from one to two chelating agents in the presence of areaction liquid selected from the group consisting of water, acetone andalcohol to produce a reaction slurry; stirring said reaction slurryuntil a constant pH is obtained; and filtering said reaction slurry toseparate the reaction product.
 2. The process of claim 1, wherein saidchelating agents are selected from the group consisting of2,4-dihydroxybenzoic acid, 2-hydroxybenzoic acid, 2,5-dihydroxybenzoicacid, o-acetamidobenzoic acid, 4-acetamido salicylic acid, salicylamideand benzoic acid.
 3. The process of claim 2 wherein said reaction iscarried out with a 1:1 molar ratio of the selected metal ions to thechelating agent.
 4. The process of claim 2 wherein said reaction iscarried out with a 5% excess of chelating agent to metal ions on a molarratio.
 5. The process of claim 3, wherein said selected metal ionsconsist of lead and copper and said selected chelating agent consists of2,4-dihydroxybenzoic acid.
 6. The process of claim 3, wherein saidselected metal ions consist of lead and copper and said selectedchelating agent consists of 2-hydroxybenzoic acid.
 7. The process ofclaim 3, wherein said selected metal ions consist of lead and copper andsaid selected chelating agent consists of 2,4-dihydroxybenzoic acid and2-hydroxybenzoic acid.
 8. The process of claim 3, wherein said selectedmetal ions consist of lead and copper and said selected chelating agentconsists of 2,4-dihydroxybenzoic acid and o-acetamidobenzoic acid. 9.The process of claim 3, wherein said selected metal ions consist of leadand copper and said selected chelating agent consists of2,4-dihydroxybenzoic acid and 4-acetamidosalicylic acid.
 10. The processof synthesizing ballistic modifiers, said process consisting of mixing asalicylate compound and a resorcylate compound on a 1:1 molar ratio in areaction liquid selected from the group consisting of water, acetone,and alcohol, wherein one of said compounds contains copper and the otherof said compounds contains lead to form a reaction slurry, stirring saidreaction slurry until a constant pH is obtained, and filtering saidreaction slurry to separate the ballistic modifiers from undesirableimpurities.
 11. The process of claim 10, wherein said salicylatecompound is monobasic cupric salicylate and said resorcylate compound islead beta-resorcylate.
 12. A ballistic modifier composition, for use insolid propellants, said ballistic modifier composition consisting of thereaction product formed by mixing different metal ions selected from thegroup consisting of lead, copper, silver, cobalt, nickel, zinc andbismuth with from one to two chelating agents in the presence of areaction liquid selected from the group consisting of water, acetone andalcohol to produce a reaction slurry; stirring said reaction slurryuntil a constant pH is obtained; and filtering said reaction slurry toseparate the reaction product.
 13. A ballistic modifier composition asset forth in claim 12, wherein said selected metal ions consist of leadand copper and said selected chelating agent consists of2,4-dihydroxybenzoic acid.
 14. A ballistic modifier composition as setforth in claim 12, wherein said selected metal ions consist of lead andcopper and said selected chelating agent consists of 2-hydroxybenzoicacid.
 15. A ballistic modifier composition as set forth in claim 12,wherein said selected metal ions consist of lead and copper and saidselected chelating agent consists of o-acetamidobenzoic acid.
 16. Aballistic modifier composition as set forth in claim 12, wherein saidselected metal ions consist of lead and copper and said selectedchelating agent consists of 2,4-dihydroxybenzoic acid and2-hydroxybenzoic acid.
 17. A ballistic modifier composition as set forthin claim 12, wherein said selected metal ions consist of lead and copperand said selected chelating agent consists of 2,4-dihydroxybenzoic acidand o-acetamidobenzoic acid.
 18. A ballistic modifier composition as setforth in claim 12, wherein said selected metal ions consist of lead andcopper and said selected chelating agent consists of2,4-dihydroxybenzoic acid and 4-acetamidosalicylic acid.